1. Field of the Invention
This invention relates to bacterial additives to dairy products and a method of preparing and using the additives.
2. Description of the Prior Art
Various bacteria, including S. diacetilactis, have been known to be used in adding diacetyl to dairy products and in inhibiting the growth of spoilage organisms in dairy products. Some patents relating to such processes are:
2,586,072 Marcoux 1952 2,971,847 Babel 1961 3,048,490 Lundstedt 1962 3,323,921 Moseley 1967
Patents relating to methods of improving flavor of dairy products using S. diacetilactis have been known since 1952 and yet only a very small percentage of dairy products are produced which take advantage of these methods of adding flavor and improving the keeping quality of dairy products. Those dairies that are utilizing patented procedures using other organisms require one to two days time in preparation of the culture additive to be used in dairy products. One of the problems existing in the Lundstedt procedure is that it concerns increasing flavor primarily and not extension of shelf life. Another problem noted in Moseley is the critical time necessary for controlling the incubation period to produce the desirable flavor. Due to the difficulty of controlling temperature and time of incubation, levels of innoculation, rate of cooling and other factors, it is hard to avoid a high production of acetaldehyde which causes an objectionable "green" flavor in the final product. Special culturing equipment in this procedure may also be required.
Many problems normally arise whenever bacteria are used. Each dairy must have trained personnel who are familar with culture handling techniques. These techniques may be such things as determining activity of starter culture, checking for bacterial contamination and for bacterial inhibitors such as antibiotics and bacteriophage. Other aspects with which this person should be familar are selection and preparation of starter medium, culture inoculation levels, determination when a culture is ripened and flavor judgment of the ripened culture to provide an optimum level of acid and aroma producing products such as diacetyl. Each dairy should also have isolated culturing facilities for propagating select strains of cultures used in the dairy industry. Using S. diacetilactis, numerous conditions must be carefully controlled to insure that excess lactic acid and other non-desirable flavor compounds are not produced.